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+<?xml version="1.0" encoding="UTF-8"?>\r
+<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"\r
+ "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">\r
+<refentry id="glGetTransformFeedbackVarying">\r
+ <refmeta>\r
+ <refmetainfo>\r
+ <copyright>\r
+ <year>2010</year>\r
+ <holder>Khronos Group</holder>\r
+ </copyright>\r
+ </refmetainfo>\r
+ <refentrytitle>glGetTransformFeedbackVarying</refentrytitle>\r
+ <manvolnum>3G</manvolnum>\r
+ </refmeta>\r
+ <refnamediv>\r
+ <refname>glGetTransformFeedbackVarying</refname>\r
+ <refpurpose>retrieve information about varying variables selected for transform feedback</refpurpose>\r
+ </refnamediv>\r
+ <refsynopsisdiv><title>C Specification</title>\r
+ <funcsynopsis>\r
+ <funcprototype>\r
+ <funcdef>void <function>glGetTransformFeedbackVarying</function></funcdef>\r
+ <paramdef>GLuint<parameter>program</parameter></paramdef>\r
+ <paramdef>GLuint<parameter>index</parameter></paramdef>\r
+ <paramdef>GLsizei<parameter>bufSize</parameter></paramdef>\r
+ <paramdef>GLsizei *<parameter>length</parameter></paramdef>\r
+ <paramdef>GLsizei<parameter>size</parameter></paramdef>\r
+ <paramdef>GLenum *<parameter>type</parameter></paramdef>\r
+ <paramdef>char *<parameter>name</parameter></paramdef>\r
+ </funcprototype>\r
+ </funcsynopsis>\r
+ </refsynopsisdiv>\r
+ <refsect1 id="parameters"><title>Parameters</title>\r
+ <variablelist>\r
+ <varlistentry>\r
+ <term><parameter>program</parameter></term>\r
+ <listitem>\r
+ <para>\r
+ The name of the target program object.\r
+ </para>\r
+ </listitem>\r
+ </varlistentry>\r
+ <varlistentry>\r
+ <term><parameter>index</parameter></term>\r
+ <listitem>\r
+ <para>\r
+ The index of the varying variable whose information to retrieve.\r
+ </para>\r
+ </listitem>\r
+ </varlistentry>\r
+ <varlistentry>\r
+ <term><parameter>bufSize</parameter></term>\r
+ <listitem>\r
+ <para>\r
+ The maximum number of characters, including the null terminator, that may be written into <parameter>name</parameter>.\r
+ </para>\r
+ </listitem>\r
+ </varlistentry>\r
+ <varlistentry>\r
+ <term><parameter>length</parameter></term>\r
+ <listitem>\r
+ <para>\r
+ The address of a variable which will receive the number of characters written into <parameter>name</parameter>,\r
+ excluding the null-terminator. If <parameter>length</parameter> is <constant>NULL</constant> no length is returned.\r
+ </para>\r
+ </listitem>\r
+ </varlistentry>\r
+ <varlistentry>\r
+ <term><parameter>size</parameter></term>\r
+ <listitem>\r
+ <para>\r
+ The address of a variable that will receive the size of the varying.\r
+ </para>\r
+ </listitem>\r
+ </varlistentry>\r
+ <varlistentry>\r
+ <term><parameter>type</parameter></term>\r
+ <listitem>\r
+ <para>\r
+ The address of a variable that will recieve the type of the varying.\r
+ </para>\r
+ </listitem>\r
+ </varlistentry>\r
+ <varlistentry>\r
+ <term><parameter>name</parameter></term>\r
+ <listitem>\r
+ <para>\r
+ The address of a buffer into which will be written the name of the varying.\r
+ </para>\r
+ </listitem>\r
+ </varlistentry>\r
+ </variablelist>\r
+ </refsect1>\r
+ <refsect1 id="description"><title>Description</title>\r
+ <para>\r
+ Information about the set of varying variables in a linked program that will be captured\r
+ during transform feedback may be retrieved by calling <function>glGetTransformFeedbackVarying</function>.\r
+ <function>glGetTransformFeedbackVarying</function> provides information about the varying\r
+ variable selected by <parameter>index</parameter>. An <parameter>index</parameter> of 0 selects\r
+ the first varying variable specified in the <parameter>varyings</parameter> array passed\r
+ to <citerefentry><refentrytitle>glTransformFeedbackVaryings</refentrytitle></citerefentry>, and\r
+ an <parameter>index</parameter> of <constant>GL_TRANSFORM_FEEDBACK_VARYINGS-1</constant> selects\r
+ the last such variable.\r
+ </para>\r
+ <para>\r
+ The name of the selected varying is returned as a null-terminated string in\r
+ <parameter>name</parameter>. The actual number of characters written into <parameter>name</parameter>,\r
+ excluding the null terminator, is returned in <parameter>length</parameter>. If <parameter>length</parameter>\r
+ is NULL, no length is returned. The maximum number of characters that may be written into <parameter>name</parameter>,\r
+ including the null terminator, is specified by <parameter>bufSize</parameter>.\r
+ </para>\r
+ <para>\r
+ The length of the longest varying name in program is given by <constant>GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH</constant>,\r
+ which can be queried with <citerefentry><refentrytitle>glGetProgram</refentrytitle></citerefentry>.\r
+ </para>\r
+ <para>\r
+ For the selected varying variable, its type is returned into <parameter>type</parameter>. The size of\r
+ the varying is returned into <parameter>size</parameter>. The value in <parameter>size</parameter> is\r
+ in units of the type returned in <parameter>type</parameter>. The type returned can be any of the\r
+ scalar, vector, or matrix attribute types returned by <citerefentry><refentrytitle>glGetActiveAttrib</refentrytitle></citerefentry>.\r
+ If an error occurred, the return parameters <parameter>length</parameter>, <parameter>size</parameter>,\r
+ <parameter>type</parameter> and <parameter>name</parameter> will be unmodified. This command will return as much\r
+ information about the varying variables as possible. If no information is available, <parameter>length</parameter>\r
+ will be set to zero and <parameter>name</parameter> will be an empty string. This situation could\r
+ arise if <function>glGetTransformFeedbackVarying</function> is called after a failed link.\r
+ </para>\r
+ </refsect1>\r
+ <refsect1 id="errors"><title>Errors</title>\r
+ <para>\r
+ <constant>GL_INVALID_VALUE</constant> is generated if <parameter>program</parameter> is not\r
+ the name of a program object.\r
+ </para>\r
+ <para>\r
+ <constant>GL_INVALID_VALUE</constant> is generated if <parameter>index</parameter> is greater or equal to\r
+ the value of <constant>GL_TRANSFORM_FEEDBACK_VARYINGS</constant>.\r
+ </para>\r
+ <para>\r
+ <constant>GL_INVALID_OPERATION</constant> is generated <parameter>program</parameter> has not been linked.\r
+ </para>\r
+ </refsect1>\r
+ <refsect1 id="associatedgets"><title>Associated Gets</title>\r
+ <para>\r
+ <citerefentry><refentrytitle>glGetProgram</refentrytitle></citerefentry> with argument <constant>GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH</constant>.\r
+ </para>\r
+ </refsect1>\r
+ <refsect1 id="seealso"><title>See Also</title>\r
+ <para>\r
+ <citerefentry><refentrytitle>glBeginTransformFeedback</refentrytitle></citerefentry>,\r
+ <citerefentry><refentrytitle>glEndTransformFeedback</refentrytitle></citerefentry>,\r
+ <citerefentry><refentrytitle>glTransformFeedbackVaryings</refentrytitle></citerefentry>,\r
+ <citerefentry><refentrytitle>glGetProgram</refentrytitle></citerefentry>\r
+ </para>\r
+ </refsect1> <refsect1 id="Copyright"><title>Copyright</title>\r
+ <para>\r
+ Copyright <trademark class="copyright"></trademark> 2010 Khronos Group. \r
+ This material may be distributed subject to the terms and conditions set forth in \r
+ the Open Publication License, v 1.0, 8 June 1999.\r
+ <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.\r
+ </para>\r
+ </refsect1>\r
+</refentry>\r
HCoop / clinton / guile-figl.git / blobdiff